Observation of large, illuminated triangle-shaped craft passing over city as we were traveling to Hospital

My daughter and I were on the way to the Hospital emergency room, as she was having a migraine that we could not get under control at home. We were traveling South from Ames Avenue on 60th Street when we noticed a set of lights proceeding North / North - West, fairly low in the sky. At first, we didn't think anything of this, as we live near a major airport, and this would not be an unusual approach for an aircraft heading for a landing. As it got close, however, my daughter said that it seemed odd that there were no strobe or red / green lights typically seen on planes that go by. All this one had was a series of white lights, of equal amplitude, that seemed to be spaced out all along and around the edges of the object. Even though she had a migraine, this was so strange that she asked me to turn off the road we were on and West, just so we might catch a better look at the object as it passed overhead. We did this, quickly, and were almost directly underneath the object as it moved on its North / North-West path. There were no airplane engine sounds, and more important, we could not see any fuselage. The object was triangular in shape, and there were lights along the edges and at the corners. We watched as it moved out of sight...never making the 'turn' to the East that one would normally expect an airplane heading for Omaha's airport to make. We then went on to the Hospital.